The Atlanta Federal Reserve published its estimate that economic growth in the second quarter of 2015 would only be 0.9% well below early expectations and not enough to compensate for the weak first quarter.

It came one day after the Commerce Department said that America's gross domestic product, the broadest measure of economic activity, expanded by only 0.2% in the first quarter this year.

"The wind of weaker economic data continuing to blow in the last day of the month of April showed a minor correction is brewing," said Jeffrey A. Carbone, managing partner at Cornerstone Financial Partners.

The negative estimate from the Atlanta Fed triggered a big sell off, especially in small cap stocks, which are much more sensitive to the U.S. economy than a major, multinational company. The Russell 2000 lost 2.1% Thursday, its second worst day this year.